What is the function of the outflow valve in the CACS?

The outflow valve plays a crucial role in the Cabin Atmosphere Control System (CACS) by managing the cabin pressure. Its primary function is to control the rate at which air exits the cabin, which is essential for maintaining a stable and safe pressure environment as altitude changes. As the aircraft climbs, the outflow valve opens at a controlled rate to allow excess cabin air to escape, thereby preventing overpressure and ensuring that the cabin pressure is regulated according to the altitude and the specific requirements for passenger comfort and safety.

This regulation is vital because if the cabin pressure were not properly managed, it could lead to discomfort or even danger for passengers and crew. Additionally, maintaining the correct pressure gradient is necessary for the safe operation of the aircraft's systems and for the health of those aboard. The valve's ability to modulate the outflow of air ensures that the cabin environment remains optimal during various phases of flight.

Other options refer to functions that are not associated with the outflow valve. Supplying oxygen, filtering pollutants, and distributing cabin lighting fall within different systems and components of the aircraft, highlighting the specific and critical nature of the outflow valve's responsibility in pressure regulation.